Recently, it has become popular to package semiconductor devices such as, for example, IC or LSI devices using a resin instead of a ceramic material.
Conventionally, encapsulating a semiconductor chip by use of resin is performed by fixing, in a mold, a lead frame having the semiconductor chip mounted thereon and by flowing a sealing resin thereinto having a high temperature of approximately 170.degree. C. When the resulting mold has been cooled down to a room temperature, since the silicon, which is a material constituting the chip, has a small thermal expansion coefficient and the sealing resin has a thermal expansion coefficient greater than that of silicon, the surface of the chip comes to receive a stress acting toward a center thereof due to shrinkage of the resin. As a result, a sliding phenomenon takes place in which an aluminum conductive layer having a large width, such as a high voltage power source conductive layer or a ground conductive layer, is forcibly biased toward the center of the chip. Such a phenomenon occurs also when cyclic temperature tests are performed.
To prevent the occurrence of the sliding phenomenon of the aluminum conductive layer, some countermeasures have been proposed in Japanese Laid Open Patent Nos. 62-111451, 62-174948 or 63-211648 which disclose that the aluminum conductive layer width is made narrow to constitute the conductive layers by a plurality of the narrower layer, or that the substantial width of the conductive layer is made small by providing a slit or slits in the layer, etc.
However, if the conductive layer or the ground conductive layer is made excessively small in width, electromigration will inconveniently occur. In addition, even if the aluminum conductive layer is divided into several parts, the effect of preventing the occurrence of the aluminum conductive layer sliding phenomenon will vanish if the divided conductive layer portion is made relatively large in width.